Field of the Invention
The invention relates to a method for operating a hearing device, wherein a sound is recorded by a microphone, the sound is analyzed with regard to its similarity with the wearer's own voice of the hearing device wearer, and a feature value is generated that indicates the extent to which the sound is similar with the wearer's own voice of the hearing device wearer. The wearer's own voice is a sound type, the feature value is compared with a threshold value, the sound is detected as own-voice depending on whether the feature value is above or below the threshold value. The hearing device is switched among a plurality of operating modes depending on whether the sound was recognized as the wearer's own voice. The invention additionally relates to a hearing device.
A corresponding method is described, for example, in the applicant's unpublished international application with file reference PCT/EP 2015/068796, corresponding to U.S. patent publication No. 2017/0256272 A1.
In the context of an analysis of the sounds recorded by means of one or more microphones, it is possible to recognize the wearer's own voice of the hearing device wearer and to switch the hearing device between different operating modes based on that recognition. Such an analysis is also referred to as “own voice detection”, or OVD for short. Such an analysis is carried out by means of an own-voice recognizer, which is usually a component of the hearing device. The microphone converts the sounds into electrical signals, which are then examined to assign the sound to a particular sound type, and more particularly, to decide whether or not the original sound is the wearer's own voice, i.e. whether the hearing device wearer is speaking or not.
From U.S. patent publication No. 2011/0261983 A1, a method is known for own-voice recognition, in which a predetermined threshold value for the recognition of the wearer's own voice is selected based on ambient sound. For this purpose, different threshold values are initially set for different sound classes among ambient sounds. During normal operation, i.e. during use of the hearing device by the hearing device wearer, the threshold value is selected based on the sound class currently present.
In the above-cited application PCT/EP2015/068796, the analysis is carried out using special filters, each of which has its own filter profile that is adapted to a respective sound, i.e. to a specific sound type or sound class. A given signal is then filtered by the filters. From the resulting filtered signal, it is then determined, for each of the filters, to what extent the original sound corresponds to the sound type to which the respective filter is adapted. For this purpose, the filter profiles are designed, for example, such that the sound to be detected is maximally attenuated based on the filter profile. In the above-mentioned application, a distinction is made in this way, according to the location of the sound, i.e. sounds which arise at different points in space relative to the hearing device are influenced differently by a respective filter. As a result, a spatial distinction, and also a distinction as to sound type, may be made due to the position of the sound relative to the hearing device. For example, nearby sounds are recognized as spatially close and then presumed to be the user's own voice, while distant sounds are recognized as such and are then presumed to be a foreign voice. Greater similarity between the actual sound and the sound to which the filter is adapted results in greater attenuation and higher degree of similarity, i.e. a higher probability that the sound being examined matches the sound type assigned to the filter. In this way, sounds may be correctly classified with a certain probability, and may be assigned to one of in particular a plurality of different sound types.
Applying different filters to a recorded signal results in correspondingly different values for the attenuation, i.e. generally similarity values, so that it is possible to decide based on these values which sound type it is. If the hearing device wearer is speaking, then the signal is attenuated more strongly by this filter and the result is a higher similarity score than in the case of another filter that is adapted, for example, to a foreign speaker in front of the hearing device wearer. By evaluating the two values, it may then be reliably determined that the hearing device wearer is speaking, i.e. that an own-voice situation is present. The evaluation takes place by forming a feature value, for example by forming a difference or quotient of the two values for the attenuation, and subsequently comparing the feature value with a predetermined stored threshold value or limit value.